Giving your body a "check engine" light

I turn the key to start the little Ford SUV I???ve rented for my visit to the University of Illinois at Urbana- Champaign, and a message flashes briefly on the dash: ???Tire pressure low.??? I ignore it. My own car is 12 years old; I???m not accustomed to a car that monitors its own health. Turns out, though, that the little Ford wasn???t kidding. The next morning I find the car has a flat tire.